Leptostylis aff. macrura Sars, 1869

Mühlenhardt-Siegel, Ute, 2014, Deep-sea Bodotriidae, Diastylidae and Pseudocumatidae (Cumacea, Crustacea) from the southeastern Atlantic, Zootaxa 3815 (3), pp. 301-341 : 313-314

Leptostylis aff. macrura Sars, 1869

( Figures 8–13 )

Described material. DIVA II, EBS #41: 1 subadult female ZMH: K 43915 ;

Additional material. DIVA II, EBS, #40-S: 1 male with developing pleopods ZMH: K 43916 ; DIVA II, EBS #41-E: 1 subadult female (dissected) ZMH: K 43917 ; DIVA II, EBS #41-S: 1 juvenile female (oostegites not yet developed) ZMH: K 43918 .

Description. Subadult female (ZMH: K 43915 ), 10 mm long ( Fig. 8 ).

Carapace, no carinae or tubercles, only few hair-like setae; pseudorostral lobes short, truncated; siphonal tube short; ocular lobe reduced; eyes missing.

Antennal notch missing; anterolateral angle not distinct; anteroventral margin of carapace serrated. Integument of carapace with many small dimples and few hair-like setae.

Five free thoracic segments visible, 0.5 times as long as carapace.

Pleon scattered with hair-like setae, 1.3 times as long as carapace and free thoracic segments combined.

Telsonic segment 1.1 times longer than wide.

Telson shorter (0.8 times) than telsonic segment and 0.4 times as long as uropod peduncle; preanal part of telson 4.3 times as long as postanal part.

Antenna 1 ( Fig. 9 , A1) relative length of peduncle articles 1 to 3: 45/27/28; article 1 with numerous hair-like and two simple setae; article 2 proximally with hair-like setae and distally with two simple setae; article 3 distally with a compound and three simple setae; accessory flagellum tri-articulated, 0.7 times as long as basal article of main flagellum; main flagellum broken behind basal article.

Maxilliped 2 ( Fig.9 , Mxp2): B/R ratio 0.7, relative length of articles I to D: 8/24/33 /24/13; basis with three simple, two pappose and two serrulate setae and several combs of thin simple setae; merus with two pappose setae and several combs of thin simple setae; carpus with six pappose setae and several combs of thin simple setae; propodus with six pappose setae; dactylus with strong terminal seta (unguis) and three simple setae.

Maxilliped 3 ( Fig. 9 , Mxp3): B/R ratio> 1.1 (basis broken proximally), relative length of articles I to D: 9/18/ 29 /25/18; basis with one broken and three pappose setae and numerous hair-like setae; ischium with one pappose seta; merus with two pappose setae; carpus with one broken and four pappose setae, propodus with a simple and a pappose seta; dactylus with a strong terminal (unguis) and three sub terminal simple setae; exopod present (broken during dissection, not figured).

Pereiopod 1 ( Fig. 9 , P1): B/R ratio 0.6, relative length of articles I to D: 9/ 12/31/33 /15; basis slightly damaged, with at least six teeth, one simple, nine pappose and several hair-like setae; ischium with a pappose seta; merus with a simple seta; carpus with two simple setae; propodus with four short simple setae; dactylus with five simple setae; exopod present.

Pereiopod 2 ( Fig. 9 , P2): B/R ratio 0.6, relative length of articles I to D: 6/16/34 /13/31; basis with three teeth and five simple setae; merus with a strong tooth-like seta; carpus with three simple setae; propodus with a hair-like and two simple setae; dactylus with six simple setae; exopod present.

Pereiopod 3 ( Fig. 10 , P3): B/R ratio 1.1, relative length of articles I to D: 17/24/ 37/13/9; basis with four simple setae; ischium and merus with two simple setae each; carpus with two terminally annulated setae; propodus with one terminally annulated seta; dactylus with a long simple seta terminally and two short simple setae subterminally; rudimentary exopod present.

Pereiopod 4 ( Fig. 10 , P4): B/R ratio 0.9, relative length of articles I to D: 18/ 25/38/12 /7; basis with five simple setae; ischium and merus with one simple seta each; carpus with one broken and two terminally annulated setae; propodus with a broken seta; dactylus with a long simple seta terminally; rudimentary exopod present.

Pereiopod 5 ( Fig. 10 , P5): B/R ratio not given (basis damaged during dissection), relative length of articles I to D: 13/23/ 42/15/7; simple seta at ischium, merus and propodus; dactylus with long terminal and a short sub terminal simple seta.

Uropod ( Fig. 10 , U): peduncle with ten cuspidate setae along inner margin, as long as telsonic segment and telson combined; exopod very slender, 0.7 times as long as endopod; endopod tri-articulated (percentage ratios: 43/ 26/31), basal article with three cuspidate setae along inner margin; distal articles each with one cuspidate seta at distal inner corner; two terminal setae.

Distribution. Cape Basin, 5054 m depth.

Remarks. Leptostylis aff. macrura is very similar to L. macrura Sars, 1869 (NE Atlantic, 73-2378 m depth) with respect to the following characters: uropod peduncle equal in length to pleonite 6 plus telson, exopod reaching beyond article 2 of endopod, telson 0.4 times as long as peduncle, no ridge or teeth on carapace in both species. There are marginal differences between both forms: the relation of the preanal to postanal part of the telson is 4.3 in the Cape Basin specimens (vs. 2.3 in the NE Atlantic specimen), the pseudorostral lobes are truncated in lateral view (vs. acute), the telson has two pairs of cuspidate setae specimens (vs. 1 pair), the number of cuspidate setae is 10 along the peduncle margin, three at endopod article 1, and one at each of the subsequent two articles (vs. eight at the peduncle, and one, one and zero at the endopod articles). Although there is a big geographical distance between the NE Atlantic (Golf of Biscay) and the Cape Basin, these differences do not appear strong enough to justify the erection of a new species.

Figures

FIGURE 8. Leptostylis aff. macrura, non-ovigerous female; habitus; scale bar: 1 mm.

FIGURE 9. Leptostylis aff. macrura, subadult female; A 1: antenna 1; Mxp 2: maxilliped 2; Mxp 3: maxilliped 3; P 1: pereiopod 1; P 2: pereiopod 2; scale bars: 0.1 mm (A 1, Mxp 2, Mxp 3) and 0.5 mm (P 1, P 2).

FIGURE 10. Leptostylis aff. macrura, subadult female; P 3: pereiopod 3; P 4: pereiopod 4; P 5: pereiopod 5; U: pleonite 6 with telson and right uropod; scale bars: 0.1 mm (P 4, P 5) and 0.5 mm (P 3, U).

FIGURE 11. Makrokylindrus (M.) meteorae, subadult female; A 1: antenna 1; Mxp 2: maxilliped 2; Mxp 3: maxilliped 3; P 1: basis of pereiopod 1; P 2: pereiopod 2; scale bars: 0.1 mm (Mxp 2) and 0.5 mm (A 1, Mxp 3, P 1, P 2).

FIGURE 12. Makrokylindrus (M.) meteorae, subadult female; P 3: pereiopod 3; P 4: pereiopod 4; P 5: pereiopod 5; U: pleonite 6, telson and left uropod; scale bars: 0.5 mm.

FIGURE 13. Makrokylindrus (M.) meteorae, subadult female; ventral part of pereionite 3 to 5 in lateral view and higher magnification; scale bar: 0.5 mm.